Intercentric gauge



Oct. 10, 1933. $w|KART 1,929,525

INTERCENTRIC GAUGE Filed June 20, 1932 2 Sheets-Sheet l INVENTOR GEORGE SWIKART Oct. 10, 1933. sw 1,929,525

INTERCENTRIC GAUGE Filed June 20, 1932 2 Sheets-Sheet 2 F 1g-4 =r- I PR 10 z r INVENTOR e y T )GEOQGE SWMART 7' BY Patented Oct. 10, 1933 I t I t v UNITED STATES PATENT OFFICE m'rnacEN-rmc GAUGE time Swikart, Riverdale, Y. Application June 20, 1932.. Serial No. 618.122

' Claims. (01. 88-20) The invention pertains to an intercentric from the corresponding and parallel line of vision gauge adapted to accurately measure the dis of the other eye. This object is accomplished tance between the centers of rotation of a pair by the use of at least one mirror in which the oi human eyes. It is very important, particueye of the observer is adapted to be reflectedand lariy in the fitting of eyeglasses having bifocal the intercentric reading taken in a position in lenses, that the spacing of the lenses of the eyewhich the center of the pupil of the reflection glasses coincides exactly with the spacing beof the observers eye in the mirror'is in direct tween the centers of rotation of the pair of eyes vertical alignment with the center of the pupil being fitted. The instrument to be described oi the eye of the patient/ do herein is capable of measuring what is commonly Other objects of the invention'will be more ()6 termed the interpupillary measurement. more apparent from the following description taken precisely and more easily than this measurement in connection with the accompanying drawings has been obtained by instruments now available. showing preferredv embodiments of .the inven Many instruments have been devised which tion, in which;

measure the interpupillary distance of the eyes 1 Figure 1 is a side elevational view'ofthe in- Z0 which distance may not be the distance between tercentric gauge'showing the manner of its use the centers of rotation of the pair of eyes being with respect to thepatient on the left whoseinfitted. The reason for this failure to measure tercentric measurement is to be taken for fitting the distance between the centers of rotation of a pair of eyeglasses by theobserver shown on the eyes lies in the fact that the patient is inthe right. structed to fix his gaze upon an object relatively Figure 2 is a top view looking down upon the near. With the eyes fixed upon such relatively intercentric gauge. 7 3 near object, the pupillary distance is less than Figure 3 is an end view of .the intercentric the. distance between the centers of rotation of gauge as viewed'from the observers position 'or the'eyes. This is understandable when it is revend of the gauge. i membered that each eye focuses directly upon the Figure 4 is a top diagrammatic illustration of object and hence the distance between the centhe manner in which'the true intercentric measters of the pupils of the eyes would represent the urement of a pair of eyes is obtained. U base of a triangle whose apex is at the object, Figure 5 is a side diagrammatic illustration so compared with the base of a triangle whose of the manner inwhichthe intercentric gauge ends represent the centers of rotation of the or instrument obtains the true intercentricmeaseyes. The latter triangle would be a triangle urement of a pair of eyes. having the same angles as the first triangle, but Figure 6 is a view showing the position of the its altitude would be greater so that its base conpatients eye and thereflection of the observers sequently is also greater than the base of the first eye in the mirror of the gauge in the position in .90

triangle having thelesser altitude. The base of which the true intercentric dimension of one of the first triangle would be the interpu'pillary the eyes ofthe patient corresponds with the inmeasurement, whereas the base of the second terpupillary dimension as observed by the obtriangle would be intercentric measurement be server when the scale reading is taken. 7 I

at) tween the centers of rotation of the. pair of eyes. Figure 7 shows another form of the invention An object of the invention-is to devise a novel which differs from the construction shown in intercentric gauge to measure accurately the dis- Figure 1 in utilizing two mirrors, whereas the tance between the centers of rotation of a pair gauge in Figure 1 uses one mirror. I 1 O y s. l I Figure 8 is a diagrammaticillustration of the 5 Another object of the invention is to construct manner in which the true intercentric dimension a novel intercentric gauge which accurately of one or a pair of eyes is measured as viewed measures the distance between the centers of from the side of the gauge or instrument rotation of a pair of eyes and which enables this Figure 9 showswhat the observer sees andthe measurement to be taken quickly and easily. relative position of the patients eye as compared 7 50 More particularly, it is an object of the invenwith the reflection of the observers eye in the tion to devise an intercentricgauge of novel demirror at the position in which theyshould apsign in which the patients vision of each eye is pear at the time the reading is taken upon the directed separately in parallel planes and accuscale forthe true intercentric dimension of the rately measuring the distance to the line of vision patients eye. h V y from the center of the gauge or instrument or The intercentric gauge now to be described not only accurately measures the spacing between the centers of rotation of a pair of human eyes, but also enables that measurement to be made quickly and easily. The principle upon which the instrument operates in its simplest form, as shown in Figure 1, is to direct the vision of one of the eyes of the patient upon the eye of the observer at all times. A mirror is supported adjacent to the eye of the patient with its reflecting surface directed towards the observer. This mirror is placed upon a level substantially bisecting the pupil of the eye of the patient. The patient is instructed to keep his vision directly upon the eye of the observer at all times and the observer moves his eye laterally with respect to the instrument or parallel with respect to the mirror until the center of the reflection of his eye in the mirror lies in a vertical plane or line with the center of the pupil of the .eye of the patient. In this position a scale reading is taken upon a scale preferably along the edge of a mirror. This procedure is followedseparately for each eye.

When the pupil of the eye of the observer as reflected in the mirror is in the same vertical plane with the center of the pupil of the eye of the patient, the line of vision of both patient and observer is exactly perpendicular to the mirror. If then the vision of both eyes is directed in the same manner at the time the reading for each eye is made, the lines of vision must be parallel because they are both perpendicular to the same mirror. It is obvious, therefore, that when the vision of each eye is directed in parallel planes, the intercentric distance between the pupils of the eyes must correspond exactly with the distance between the centers of rotation of the eyes of the patient.

The gauge preferably utilizes a vertically disposed shield 10. The shield 10 serves also as a frame to support the other devices which are provided with the gauge in order to make the intercentric measurement. It is clear that the shield may be a simple frame without performing the function of shielding the vision of one eye of the patient, such as the right eye, from the vision of the right eye of the observer upon the other side of the frame or shield. The shield therefore assists in preventing thepossibility of the patients eye wandering from being directed to the left eye of the observer.

The shield 10 carries a nose rest 13 which preferably is a U-shaped or a modified U-shaped structure to fit over the bridge of the nose of the patient P. The nose rest 13 carries a vertical guide or slide 1?: having a vertical slot 15 therein in which a pair of guide screws 16 are received.

This construction provides vertical adjustability I for the nose rest.

The slide or guide 14 is connected by a link 17 to an adjusting nut 18;. The link 1'? ispivotally mounted upon a pivot 23 in the bracket 19 carried by the shield 10 and the nut 18 is mounted upon a screw 22 also carried by the shield 10. The adjusting nut 18 carries a groove 20 in which rollers 21 upon the connecting link 17 is received. By rotating the adjusting nut 18. the nut moves vertically upon the screw 22, which vertical movement is transmitted by link 17 to the slide 14 and the nose rest 13 and thereby obtains vertical adjustment thereof.

The shield 10 carries a handle 25 for conveniently holding the intercentric gauge when it is being used. The handle 25 is preferably secured to the end of the screw 22, although it is clear oeaeee that it may be provided at any desired point upon the gauge.

In order to steady the observer while he is taking a reading of the patients intercentric dimension, a head rest 30 is provided upon the shield 19 at the end thereof opposite from the nose rest 13. The head rest is a transversely extending bar or plate supported upon the shield if) by means of the brackets 31. This head rest extends at right angles to the shield 15). The observer rests his forehead upon the head rest 30 and moves or slides his head along its surface when obtaining vertical alignment between the center of the patients pupil and the center of the reflection of the observers own eye in the mirror as will be described.

A mirror 35 is carried upon the shield 10 at the end thereof adjacent to the nose rest 13 and is supported by a bracket 36 which holds the mirror at right angles to the shield 10. The reflect- 1 e mirror faces the observer 0. mirror preferably is a single mirror which extends upon both sides of the shield 10. A scale 37, graduated usually in millimeters and centimeters, is provided at or adjacent the edge of the mirror 35 and may be etched into the surface of a glass mirror. The scale or graduations 37 may be one continuous scale or it may consist of two scales extending outwardly along the edge of the mirror from the center or shield 10. With the separate scales, as shown in Figure 3, the distance of each eye from the nose of the patient or the center of the gauge is obtained as a separate reading. The intercentric measurement between the centers of rotation of the patients eyes will then be obtained by adding the scale readings for each eye.

in order to prevent the patient from being diverted and the eye to be measured from being influenced by the vision of the other eye, a screening means is utilized to obstruct the vision of the other eye. The screen carried by the shield 10 is adapted to obstruct the vision of one eye only. Either eye may be obstructed merely by moving the screen 40 from one side to the other of the shield 18. The movement of the screen 40 is obtainedpreferably by mounting the screen upon th pivot ll which is supported on the shield 10 by means of the brackets 42. The shield 10 has a slo i3 therethrough so that the screen 40 is pivoted or movable through the slot into a posltion to screen either the left or the right eye of the patient. The screen 40 may have an outwardly bent stop id at each end of the screen, which stop engages the shield 10 when it has been fully pivoted into position to shield one or the other eye.

The manner in which the intercentric dimension of the patients eyes is obtained is shown diagranimatically in Figures 4 and 5. The patients left eye PL and the right eye PR are shown adjacent to the mirror 35 and parallel thereto. The vision of the patient is directed over the mirror 35 while the vision of the left eye PL is obstructed by the screen 40. The observers right eye OR and the left eye OL are shown with their vision directed tewards'the patients eyes and parallel with the mirror 35. The vision of the observers right eye OR is obstructed by the screen 40 in the same way that the vision of the patients left eye PL is also screened thereby.

The patient is instructed to direct the vision. of his right eye PR directly upon the left eye CL of the observer. The observer 0 moves his head until the reflection B of his left eye 0L is in vertical led alignmentwith the patients righteye PR. This position is shown in Figure 6 where the center of the pupil of the eye of the patient as observed by the observer's left eye OL is the trueintercen- ,tric measurement of the patients righteye PR; In thisposition the vision of the patients right eye PR is being directed parallel to the shield 10 r and perpendicular to the mirror 35 in which-position the center of the pupil of the patients right eye PR is in direct line with the center of rotation of the right eye so that a reading of the center of the pupil from the screen '10 will correspond tients left eye PL.

A side view oflthe position of the eyes and the position of the mirror is shown in Figure 5. The mirror 35 is shown with its top edge substantially bisecting the view of the patients right eye in a horizonal plane. By this construction the graduations of the scale 3''! upon the upper edge of themirror 35 are brought directly to the center of the pupil of the patients eye PR so that the center of the pupil maybe exactly and easily delermined to measure the intercentric dimension of the patients eye. Themirror 35 with its scale 37 need not, of course, be so positioned, butmayv be somewhatbelow-thehorizontal center of the patients eye. Where the edge of the mirror is below the horizontal center of the patients eye, it is not quite as simple to align the center of the pupil of the eye with agraduation upon the edge of the scale but this does not prevent an accurate dimension from being read. The reading is not at all difficult to make, as shown in Figure 9, when the center of the eye is somewhat above the edge of the mirror 35. r

As discussed above, the true intercentric dimension between the centers of rotation of a.

the vision of each eye is parallel to the other and hence the intercentric dimension of the pupils of the eyes of the patient is the same as the inter centric dimension of the centers "of rotation of the eyes. 7

In Figure 7 a modified construction is shown which corresponds essentially in every detail with the construction shown in Figure 1. One of the diiferenc'es in this construction'is that the mirror 35 is tilted slightly so that its reflecting surface is directedat a slight angle upwardly. The reason for this tilting will be discussed more fullyhereinafi'er. I

A second mirror is also provided in the construction shown in Figure 7, which mirror is carried by the shield 10 adjacent to the eye of the observer 0. This mirror is supported upon the shield 10 by a bracket 51 which holds the mirror 50 at right angles to the shield 10 and with an upward tilt at a slight angle. The reflecting surface of the mirror 50 is directed towards the patient P and hence the slight tilt in the mirror directs the reflecting surface at a slight tilt up-.

wardly. In all other respects, the two construetions of Figures 1 and 7. are identical. I With the gauge shown in Figure 7, the patient P is instructed to direct the vision ofthe eye to be measured upon the mirror 50 so that-he islooking-directly at the reiiection of his own eye therein. With the patients vision so directed, then the vision of that eye is perpendicular to the mirror 50 and hence is parallel tothe shield 10. The observer 0 now moves his head along the head rest 30 until thereflectionof the observers eye in the mirrior 35- is in vertical alignment with the patients eye as shownin Figure 9. In this position the vision of the observer is perpendicular to the mirror 35 and hence parallel to the screen 10 and in the same plane as the vision of the patient. The reading upon the scale 37 of the graduation which. bisects the center of the patients pupil-is also the true intercentric dimension of the center of rotation of the patients eye. The'intercentric reading of a patients eyes is taken essentially in the same manner with the gauge. of Figure '7 as with the gauge of Figure" 1 and the only difference is in the patient directing his vision'upon a mirror rather than upon the observers eye. V

A diagrammatic illustration of the position of the patients eye P and the observers eye Ois shown inFigure 8 and thereflection R of the observers eyein the mirror 35, shownin dotted lines at. the left of the illustration, as well as the reflection R of the patients eye in the mirror .50 shown in dotted lines at the right of the in the art in the configuration, composition and disposition of the componentelements going to .make up the invention, as a whole, as well as in the selective combination or application of the respective elements, and nolimitation is intended by the phraseology of the foregoing descripion or i lustrations in the accompanying drawings, except as indicated in the appended claims.

What is claimed is:-

1. An intercentric gauge comprising a frame, a nosev rest carried thereby; a mirror carried by the frame and extending at right angles thereto, the mirror facing away from the nose .rest

and being spaced. vertically therefrom so that.

the eye ofthe patient is adjacent the edge of the mirror; theyplane of the mirror'being disposed substantially vertically so that an'observer'will see his eye therein when taking an intercentric reading, and a scale alongthe edge of the mirror.

2. An intercentric gauge comprising a frame, a nose rest carried thereby, a rnirror carried by the frame and extending at right angles thereto, the mirror facing away from the nose rest,

the plane of the mirror being disposed substantially vertically so that an observer will see his eye therein when taking an inter'centric reading, a scale along the edge of the mirror, and

central shield, a nose rest carried .at the end of Y the shield, a mirror carried by the shield and extending at right angles thereto, the mirror facing away from the nose rest and being spaced vertically therefrom so that the eye of the patient is adjacent the edge of the mirror, the plane of the mirror being disposed substantially vertically so that an observer will see his eye therein when taking an intercentric reading, and a scale along the edge of the mirror.

4. An intercentric gauge comprising a fixed central shield, a nose rest carried at the end of the shield, a mirror carried by the shield adjacent the end thereof and extending at right angles thereto, the plane of the mirror being disposed substantially vertically so that an observer will see his eye therein when taking an intercontrio reading, a scale along the edge of the mirror, and means adjusting the position of the nose rest vertically relatively to the mirror to bring the eye of the patient adjacent the edge of the mirror.

5. An intercentric gauge comprising a fixed central shield, a nose rest carried at the end of the shield, a mirror, carried by the frame and extending outwardly from both sides of and at right angles to the shield, the plane of the mirror being disposed substantially vertically so that an observer will see his eye therein when taking an intercentric reading, a scale along the edge of the mirror, and a screen upon one side of the shield to obstruct the vision of one eye and movable to the other side of the screen to obstruct the vision of the other eye and clear the vision of the first eye.

6. An intercentric gauge comprising a central frame, a nose rest carried at one end thereof, a mirror carried by the frame and extending at right angles thereto and to the nose rest, the mirror being spaced vertically from the nose rest so that the eye of the patient is adjacent the edge of the mirror, the plane of the mirror being disposed substantially vertically so that an observer will see his eye therein when taking an intercentric reading, a scale along the edge of the mirror, and a head rest at the other end of the frame from the nose rest and extending at right angles to the frame.

'7. An intercentric gauge comprising a central frame, a nose rest carried at one end thereof, a mirror carried by the frame adjacent the end thereof and extending at right angles to the frame, the mirrored surface facing the other end of the frame, the plane of the mirror being disposed suostantially vertically so that an observer will see his eye therein when taking an intercentrio readingfa scale along the edge of the mirror, and a second mirror at the other end of the frame having its mirrored surface facing towards the other mirror.

8. An intercentric gauge comprising a central and vertically disposed shield, a nose rest at one end thereof, a vertical guide carrying the nose rest, a handle projecting downwardly from the shield, screwthreads on the handle, a nut on the screw threads, means operably connecting the nut with the nose rest for vertical adjustment of the latter, a mirror carried by the shield adjacent the end thereof and extending at right angles to the shield, the mirrored surface facing towardthe other end of the shield, and a scale along the edge of the mirror.

9. An intercentric gauge comprising a central and vertically disposed shield, a nose rest at one end thereof, a mirror carried by the shield adjacent the end thereof carrying the nose rest and extending at right angles to the shield, the mirrored surface facing toward the other end of the shield, the plane of the mirror being disposed substantially vertically so that an observer will see his eye therein when taking an intercentric reading, a scale along the edge of the mirror, and a second mirror at the other end of the shield having its mirrored surface facing toward the other mirror.

10. An interoentric gauge comprising a central frame, a nose rest at one end thereof, means sup porting the nose rest for vertical adjustment, a mirror carried by the frame adjacent the end thereof carrying the nose rest and extending at right angles to the frame, the mirrored surface facing toward the other end of the frame, the plane of the mirror being disposed substantially vertically so that an observer will see his eye therein when taking an interoentric reading, a scale along the edge of the mirror, and a second mirror at the other end of the frame having its mirrored surface facing toward the other mirror.

11. An intercentric gauge comprising a central and vertically disposed shield, a nose rest at one end thereof, means supporting the nose rest for vertical adjustment, a mirror carried by the shield adjacent the end thereof carrying the nose rest and extending at right angles to the shield, the mirrored surface facing toward the other end or the shield, the plane of the mirror being disposed substantially vertically so that an observer will see his eye therein when taking an intercentric reading, a scale along the edge of the mirror, and a second mirror at the other end of the shield having its mirrored surface facing toward the other mirror.

12. An 'intercentric gauge comprising a central frame, a nose rest at one end thereof, a screen obstructing the vision of one eye and movable into position'to obstruct the vision of the other eye and clear the vision of thefirst eye, a mirror carried by the frame adjacent the end thereof and extending at right angles to the frame, the mirrored surface facing toward the other end of the frame, the plane of the mirror being disposed substantially vertically so that an observer will see his eye therein when taking an intercentric reading, a scale along the edge of the mirror, and a second mirror at the other end of the frame having its mirrored surface facing toward the other mirror.

13. An intercentric gauge comprising a central and vertically disposed shield, a vertically adjustable nose rest at one end thereof, a mirror carried by the shield adjacent the end thereof and extending at right angles to the shield, the mirrored surface facing toward the other end of the shield and tilted upward at a slight angle, a scale along the edge of the mirror, a second mirror at the other end of the shield having its mirrored surface facing toward the other mirror and tilted upward at a slight angle, a slot in the shield, and a screen pivoted in the slot and swingable into position to obstruct the vision of either eye.

14. An intercentric gauge comprising a central and vertically disposed shield, a nose rest at one end thereof, a vertical slide carrying the nose rest, a handle attached to the shield, screw threads on the handle, a nut on the screw threads, means connecting the nut and the nose rest for vertical adjustment of the latter, a vertically disposed mirror carried by the shield adjacent the end thereof and extending at right angles to the shield, the mirrored surface facing toward the other end of the shield and tilted upward at a slight angle, a scale along the edge of the mirror, a second mirror at the other end of the shield having its mirrored surface facing toward the other mirror and tilted up'vv'ard at a slight angle,

a slot in the shield, a screen carried by the shield 15. An intercentric gauge comprising a fixed i the shield, a mirror carried by the shield and extending at right angles thereto, the mirror facing away from the nose rest, the plane of the mirror being disposed substantially vertically so that an observer will-see his eye therein when taking an intercentric reading, and a scale along the edge of the mirror.

GEORGE swiKAR'r.

central shield, a nose rest carried at the'end of 

